Took me a while to realise this thread wasn't satire after all...
Focus is essential to the game, IMO. It forces decision-making in almost all aspects of its uses, which enhances the depth of the game. It also rewards good play and good decision-making.
To illustrate the first point, the presence of Focus makes deciding between a Barrel Roll or just a Focus an important decision with actual consequences for failure. If I'm thinking about Barrel Rolling but I'm not sure if it will get me out of arc or get me a shot, I can always fall back on the Focus as a last resort. The decision then becomes whether to risk making an error with my BR/Boost and be without Focus but potentially not getting shot back at all, or take the safe option and just Focus, knowing it will be generally useful but potentially getting shot at when I didn't need to. More meaningful decisions like that makes the game deeper and more interesting.
Focus can also be seen as a reward for good play. If I position my ship well so I'm out of my enemy's arc my reward is the generally useful Focus action to enhance my shots. If I get to range 3 behind an obstacle to avoid the worst of my opponent's fire the reward for my good play is enhancing my 4-5 green dice with a Focus rather than the relatively weaker (in this case) Evade. Also, the Focus action being useable on offense or defence means it creates more decision points throughout the game, allowing for a much deeper, more interesting experience. Do I spend my token on the attack, knowing I may need it when defending later? Or vice versa if I'm shooting later in the round? These are all decisions promoted by the Focus action.
Without the Focus action there's much less punishment for not BR out of arc because you misjudged the move. There's no real decision to be made about spending an Evade token since it's pretty much always best to spend it as soon as possible (not always, but usually). I don't need to make meaningful decisions on offensive modifiers either. In short, removing Focus from the game might actually be one of the worst ideas I can think of from a game design and depth point of view.